From: Andrea Arcangeli <andrea@suse.de>
To: William Lee Irwin III <wli@holomorphy.com>,
Jack Steiner <steiner@sgi.com>,
linux-kernel@vger.kernel.org
Subject: Re: RCU scaling on large systems
Date: Fri, 7 May 2004 19:53:58 +0200 [thread overview]
Message-ID: <20040507175358.GD3829@dualathlon.random> (raw)
In-Reply-To: <20040501211704.GY1445@holomorphy.com>
On Sat, May 01, 2004 at 02:17:04PM -0700, William Lee Irwin III wrote:
> On Sat, May 01, 2004 at 07:08:05AM -0500, Jack Steiner wrote:
> > On a 512p idle 2.6.5 system, each cpu spends ~6% of the time in the kernel
> > RCU code. The time is spent contending for shared cache lines.
>
> Would something like this help cacheline contention? This uses the
> per_cpu data areas to hold per-cpu booleans for needing switches.
> Untested/uncompiled.
>
> The global lock is unfortunately still there.
I'm afraid this cannot help, the rcu_cpu_mask and the mutex are in the same
cacheline, so it's not just about the global lock being still there,
it's about the cpumask being in the same cacheline with the global lock.
next prev parent reply other threads:[~2004-05-07 21:17 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-01 12:08 RCU scaling on large systems Jack Steiner
2004-05-01 21:17 ` William Lee Irwin III
2004-05-01 22:35 ` William Lee Irwin III
2004-05-02 1:38 ` Jack Steiner
2004-05-07 17:53 ` Andrea Arcangeli [this message]
2004-05-07 18:17 ` William Lee Irwin III
2004-05-07 19:59 ` Andrea Arcangeli
2004-05-07 20:49 ` Jack Steiner
2004-05-02 18:28 ` Paul E. McKenney
2004-05-03 16:39 ` Jesse Barnes
2004-05-03 20:04 ` Paul E. McKenney
2004-05-03 18:40 ` Jack Steiner
2004-05-07 20:50 ` Paul E. McKenney
2004-05-07 22:06 ` Jack Steiner
2004-05-07 23:32 ` Andrew Morton
2004-05-08 4:55 ` Jack Steiner
2004-05-17 21:18 ` Andrea Arcangeli
2004-05-17 21:42 ` Andrew Morton
2004-05-17 23:50 ` Andrea Arcangeli
2004-05-18 13:33 ` Jack Steiner
2004-05-18 23:13 ` Matt Mackall
-- strict thread matches above, loose matches on Subject: below --
2004-05-20 11:36 Manfred Spraul
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